HIV genital shedding may persist despite effective combination anti- retroviral therapy, thereby posing a high risk for transmission of HIV via sexual contract. One important factor that may be associated with persistent HIV shedding is the presence of CMV shedding, which has been independently associated with HIV-1 shedding in the genital tract in cross section studies in both men and women. However, the exact frequency, time pattern, the quantitative aspects, factors leading to CMV shedding relative to HIV shedding in the female genital tract is only poorly defined. Furthermore, virologic and immunologic factors of genital shedding are not known. The hypothesis of this proposal is that CMV up-regulates HIV replication in the female genital tract. The project is aimed at examining the frequency, temporal pattern, and quantitative aspects of CMV shedding, as well as the underlying mechanisms of the CMV-HIV interaction in a prospective cohort study of HIV infected women. Over a period of several months study subjects will be tested daily for genital CMV DNA, HSV DNA, and HIV-1 RNA and DNA by quantitative PCR. HSV is included because HSV lesions contained HIV RNA, and HSV may also up-regulate HIV replication in the genital tract. Subsequently, women who are identified to shed both CMV and HIV and are free of bacterial cervico-vaginal virus infections will be enrolled in a prospective double- blind placebo-controlled, cross-over study to selectively suppress HSV with valacyclovir, or to suppress both HSV and CMV with valganciclovir. The third aim examines the mechanisms of CMV shedding in HIV-infected women. It is our hypothesis that persistent high-level shedding of CMV is due to cervical infection with multiple strains of CMV. To examine this hypothesis, CMV shedding detected in the prospective cohort study will be correlated with epidemiologic factors (e.g. age, number of partners, frequency of intercourse) and with DNA- based strain typing information from genital tract specimens to determine whether genital tract information with multiple strains increases the risk of genital tract CMV or HIV shedding. To examine the hypothesis that cervical CMV shedding is related to immunologic levels of systemic or local CMV-specific immunity, we will also measure these immune parameters in women undergoing serial genital tract specimen collection. The results of these studies will improve our understanding of the interrelationship of CMV, HSV and HSV-1 shedding in the female genital tract and provide insight in the pathogenesis of CMV shedding in the female genital tract. By suppressing CMV and/or HSV shedding with anti-viral chemotherapy we will get further insight into whether there is a causative relationship between CMV and HIV-1 shedding and possibly obtain proof-of-concept data for interventions with the ultimate goal to reduce HIV transmission.